Blank mask and method of fabricating the same

Abstract

A method of fabricating a blank mask. The method includes forming a light-shielding film on a light-transmissive substrate to form an optical substrate; forming a photoresist layer on the light-shielding film; and removing droplets, generated in the forming of the photoresist layer, from a side surface of the light-transmissive substrate, wherein the number of droplet-type adsorption, derived from the droplets, on the side surface of the light-transmissive substrate, is less than 3 per cm2.

1 . A method of fabricating a blank mask, the method comprising:
 forming a light-shielding film on a light-transmissive substrate to form an optical substrate;   forming a photoresist layer on the light-shielding film; and   removing droplets, generated in the forming of the photoresist layer, from a side surface of the light-transmissive substrate,   wherein the number of droplet-type adsorption, derived from the droplets, on the side surface of the light-transmissive substrate, is less than 3 per cm 2 .   
     
     
         2 . The method according to  claim 1 , further comprising seating the optical substrate on a chuck,
 wherein the forming of the photoresist layer comprises:   dropping a photoresist composition on the light-shielding film;   rotating the optical substrate; and   spraying compressed air between the optical substrate and the chuck,   wherein the rotating of the optical substrate and the spraying of the compressed air are simultaneously performed.   
     
     
         3 . The method according to  claim 2 , wherein the chuck comprises:
 a support part for supporting the optical substrate; and   a guide part disposed on a side surface of the optical substrate,   wherein in the rotating of the optical substrate, the optical substrate and the guide part are simultaneously rotated, and   the compressed air is sprayed between the guide part and the side surface of the optical substrate.   
     
     
         4 . The method according to  claim 1 , further comprising seating the optical substrate on a chuck,
 wherein the forming of the photoresist layer comprises:   dropping a photoresist composition on the light-shielding film;   rotating the optical substrate; and   applying vacuum between the side surface of the optical substrate and the chuck,   wherein the rotating of the optical substrate and the applying of the vacuum e are simultaneously performed.   
     
     
         5 . The method according to  claim 4 , wherein the chuck comprises:
 a support part for supporting the optical substrate; and   a guide part disposed on the side surface of the optical substrate,   wherein in the rotating of the optical substrate, the optical substrate and the guide part are simultaneously rotated, and   the vacuum is applied between the guide part and the side surface of the optical substrate.   
     
     
         6 . The method according to  claim 1 , wherein the number of the droplet-type adsorption formed on a lower surface of the light-transmissive substrate is less than 4 per cm 2 . 
     
     
         7 . The method according to  claim 1 , wherein the optical substrate comprises the droplet-type adsorption,
 the droplet-type adsorption has an island shape, and   the droplet-type adsorption has a diameter ranging from about 0.01 μm to about 10 μm.   
     
     
         8 . The method according to  claim 7 , wherein the number of the droplet-type adsorption formed on a side surface of the light-transmissive substrate ranges from about 0.05 per cm 2  to about 1 per cm 2 . 
     
     
         9 . A blank mask, comprising:
 a light-transmissive substrate;   a light-shielding film disposed on the light-transmissive substrate; and   a photoresist layer disposed on the light-shielding film and comprising a photosensitive resin, and   on a side surface of the light-transmissive substrate, the number of droplet-type adsorption comprising the photosensitive resin is less than 3 per cm 2 .   
     
     
         10 . The blank mask according to  claim 9 , wherein the number of the droplet-type adsorption formed on a lower surface of the light-transmissive substrate is less than 4 per cm 2 . 
     
     
         11 . The blank mask according to  claim 9 , wherein the number of the droplet-type adsorption formed on a side surface of the light-transmissive substrate is less than 2.5 per cm 2 . 
     
     
         12 . The blank mask according to  claim 11 , wherein the number of the droplet-type adsorption formed on the side surface of the light-transmissive substrate is less than 0.5 per cm 2 . 
     
     
         13 . The blank mask according to  claim 10 , wherein the number of the droplet-type adsorption formed on a lower surface of the light-transmissive substrate is less than 2 per cm 2 . 
     
     
         14 . The blank mask according to  claim 9 , wherein the droplet-type adsorption has a diameter ranging from 0.01 μm to 10 μm. 
     
     
         15 . A blank mask, comprising:
 a light-transmissive substrate;   a light-shielding film disposed on the light-transmissive substrate;   a photoresist layer disposed on the light-shielding film and comprising a photosensitive resin; and   a droplet-type adsorption formed on a side surface of the light-transmissive substrate, comprising the photosensitive resin and having an island shape,   wherein the droplet-type adsorption formed on the side surface of the light-transmissive substrate has a density ranging from about 0.05 pieces per cm2to about 3 pieces per cm 2 .   
     
     
         16 . The blank mask according to  claim 15 , wherein the droplet-type adsorption is formed on a lower surface of the light-transmissive substrate, and
 the droplet-type adsorption formed on the lower surface of the light-transmissive substrate has a density ranging from about 0.05 pieces per cm 2  to about 3 pieces per cm 2 .   
     
     
         17 . The blank mask according to  claim 16 , wherein the droplet-type adsorption comprises first droplet-type adsorption having a diameter ranging from about 0.01 μm to about 0.04 μm, and the number of the first droplet-type adsorption ranges from about 0.05 per cm 2  to about 0.5 per cm 2 . 
     
     
         18 . The blank mask according to  claim 17 , wherein the droplet-type adsorption comprises second droplet-type adsorption having a diameter ranging from about 0.04 μm to about 0.3 μm, and
 the number of the second droplet-type adsorption ranges from about 0.05 per cm 2  to about 0.5 per cm 2 . 
 
     
     
         19 . The blank mask according to  claim 18 , wherein the droplet-type adsorption comprises third droplet-type adsorption having a diameter ranging from about 0.3 μm to about 3 μm, and the number of the third droplet-type adsorption ranges from about 0.05 per cm 2  to about 0.5 per cm 2 . 
     
     
         20 . The blank mask according to  claim 15 , wherein the droplet-type adsorption formed on a side surface of the light-transmissive substrate has a density ranging from about 0.05 pieces per cm 2  to about 1 piece per cm 2 .